1. Field of the Invention
The present invention relates to a seal structure for a motor vehicle, and more particularly to a seal structure for a motor vehicle provided with a door mirror bracket for retaining a door mirror.
2. Description of the Prior Art
A motor vehicle is ordinarily provided with a triangular door mirror bracket which is mounted on a front end of a door belt line. Meanwhile, to an upper half portion of a door opening of a car body is attached a roof weather strip for sealing a periphery of a front door glass. A roof weather strip is continuously attached to a front pillar, a roof side, and a center pillar. When a front door is closed, a periphery of each of a door mirror bracket and a front door glass comes into pressure contact with the roof weather strip (Japanese unexamined Utility Model publication No. Sho 61-122938).
FIGS. 6 and 7 illustrate a joint portion of the door mirror bracket 4 and a front upper end of a door inner panel 31 of the conventional front door 3.
A door weather strip 2 composed of a tubular extruded body is attached along a periphery of the front door 3. At a front end of the door weather strip 2 is formed a die-molded end portion 20 which covers a front upper corner of the door inner panel 31 and a lower portion of the door mirror bracket 4. The door inner panel 31 locates on an inside of the door mirror bracket 4 to form a step between the door inner panel 31 and the door mirror bracket 4. Accordingly, an upper part 21 of the end portion 20, which covers the lower portion of the door mirror bracket 4, is formed into an inclined surface. In the drawings, reference numeral 32 designates a door outer panel, 33 designates a door outer weather strip, 34 designates a trim for covering an inside surface of the front door 3.
When the front door 3 is closed, the periphery of the front door glass, a front edge of the door mirror bracket 4, and the door weather strip 2 continuously come into pressure contact with the roof weather strip 1 to effect a seal between the front door 3 and the door opening. However, the sealing performance of the roof weather strip 1 tends to be insufficient in the end portion 20 of the door weather strip 2 because of the formation of the inclined upper part 21.
Recently, in order to improve the sealing performance of the roof weather strip, there has been employed a two-point seal structure wherein the roof weather strip comes into contact with an opposite door member at two points thereby forming two seal lines with the opposite door member.
In the seal structure illustrated in FIGS. 6 and 7, the roof weather strip 1 is provided with a tubular main seal portion 11 and a lip-shaped sub-seal portion 12. The seal portions 11 and 12 come into pressure contact with the opposite door member, respectively, thereby forming two parallel seal lines, that is a main seal line S.sub.1 (mark o) and a sub-seal line S.sub.2 (mark x). The main seal line S.sub.1 is continuously connected to the seal line S.sub.1 ' (mark o) of the door weather strip 2 which is to come into pressure contact with a lower half portion of the door opening while the sub-seal line S.sub.2 is connected to the seal line S.sub.1 ' in the inclined upper part 21 of the end portion 20.
However, the experiments by the present inventors have proved that the sub-seal line S.sub.2 is liable to be disordered or broken in the end portion 20, especially in the inclined upper part 21 thereof so as not to be continuously connected to the seal line S.sub.1 ' thereby lowering the sealing performance of the roof weather strip in the end portion 20.